Compass



Feb 27, 195% F. E. VAUGHAN 9 9 COMPASS Filed May 20, 1948 Bnveutor,

Gitorncy Patented Feb. 27, 1951 UNITED STATES PATENT OFFICE COMPASS Francis E. Vaughan, Pasadena, Calif.

Application May 20, 1948, Serial No. 28,232

2 Claims.

My invention relates to new and useful improvements in compasses.

The object of my invention is to provide a compass having bifurcated legs with friction means for holding said bifurcated legs in desired angular relationships.

Another object of my invention is to provide a handle for manipulating said compass, means being provided whereby said handle is so constrained that its axis remains at, or near, the

bisector of the angle between the legs as said legs are separated or brought together.

Another object of my invention is to provide a spacer for holding apart the upper portions of each of the bifurcated legs.

Another object of my invention is to provide a compass having legs bifurcated near the hinge in which a slidable erecting piece also serves as a spacer for holding apart the upper portions of each of the bifurcated legs.

Another object of my invention is to provide a compass inv which the axis of symmetry of the slidable member is always at, or near, the bisector of the angle formed by the legs of the compass.

My invention has many other objects which will be apparent from a study of the following specifications read in connection with the accompanying drawings.

Referring to the drawings:

Fig. 1 is an upright front view of a compass embodying my invention;

Fig. 2 is an upright side view showing the bifurcated construction of the compass legs;

Fig. 3 is an upright front view of the erecting piece with the handle attached;

Fig. 4 is an upright side view of the erecting piece with the handle attached;

Fig. 5 is an enlarged fragmentary upright view of the hinge portion of the compass with a saucer-shaped member and its retaining screw removed to show structural relationships; and

Fig. 6 is a section taken along the line 5-6 in Fi 1.

Referring to said drawings, the numeral I I indicates a cylindrical hinge pin which carries the upper ends of the bifurcated legs I2 and I3, said legs being held against the hinge pin II by the saucer-shaped springs I4, which engage grooves I5 in the bifurcated leg I2 and grooves I6 in the bifurcated leg I3. As shown in the drawings, each of the bifurcated legs is constructed from two pieces fastened together adjacent their lower ends, but it is only necessary that the legs be bifurcated at their upper ends. The saucer- 2, shaped springs I4 are fastened to the hinge pin II by screws IT.

A slidable erecting piece I8 is positioned between the branches of the bifurcated legs I2 and I3, and carries a handle stem E9 to which is affixed the handle 20. The erecting piece I8 is provided with a slot 2I having parallel sides 22 and 23 fitting closely against the hinge pin II.

The erecting piece I8 is operatively connected to each of the bifurcated legs I2 and I3. As an instance of this arrangement, the erecting piece It is provided with two pins 24, which are preferably, but not necessarily, firmly fitted to said erecting piece. These pins 24 extend from either side of the erecting piece I8 into slots 25 in at least one of the branches of each of the legs I2 and I3. These slots lie to either side of the hinge pin II and are elongated in directions approximately radial with respect to the center of said hinge pin. The upper and lower sides 26 and 21 of these slots 25 are parallel and fit closely against the pins 24.

As the lower ends of the legs are spread apart the legs I2 and. I3 pivot'about the hinge pin II,

. thus causing the slots 25 to rise and carry with them the pins 24 and the slidable erecting piece I8, the slot 2I being provided to permit this rising of said erecting piece. Conversely, when the lower ends of the compass legs are brought together the erecting piece is lowered. Although the opening and closing of the legs causes the erecting piece I8 to be raised and lowered, it

will be noted that the pins 24 prevent it from rotating in either direction about the hinge pin I I it follows that the axis of the handle 29, produced downward between the legs I2 and I3, will continue to bisect the angle between said legs as it is increased or diminished by opening or closing the legs. Thus the handle remains in a convenient position above the legs and at the same time is maintained so rigidly with respect to them as to afford a convenient means for manipulating the entire device.

It will be noted that the friction between the slidableerecting piece I8 and the bifurcated legs I2 and I3 is of two kinds, friction due to the motion of rotation of said legs about the hinge pin I I and friction due to the motion of the erecting piece I 8 as the legs I2 and I3 are opened and closed. Another source of friction is at the points of contact between the grooves I5 and I6 in the branches of the compass legs and the saucershaped springs I4. When properly controlled, the friction from these various sources tends to hold the compass legs at any angle at which they may be set, at the same time leaving them adjustable when suificient force is applied to change this angle, and thus the spacing of the lower ends of the legs. In a broad sense, the total friction can be controlled by the pressure of the saucer-shaped springs 14 upon the branches of the legs 12 and 13. Since the screws I! firmly press the springs 14 against the hinge pin H, it follows that the pressure of these springs against the branches of the compass legs will be decreased as the effective length of the hinge pin II is increased and will be increased as the effective length of the hinge pin II is decreased. The efiective length of the hinge pin can be changed by actually cutting the hinge pin itself, if it be too long, or by placing a thin washer between the saucer-shaped springs 14 and the hinge pin, if it be too short. The pressure of the saucer-shaped springs [4 against the branches of the compass legs l2 and I3 is also influenced, in some measure, by the thickness of said springs and the material of which they are constructed. Obviously, the thinner they are, the less the pressure, and, conversely, the thicker they are, the greater the pressure. It is clear that when the springs are sufficiently thin to yield appreciably when tightened against the hinge pin H by means of the screws H, the adjustment by changing the effective length of the hinge pin 1 1 becomes less critical than when they are very stiff.

One of the advantages of my compass is that the hinge mechanism is adapted to use with bifurcated legs, a type of legs easily constructed and contributing toward making a compass of light weight.

Another advantage is that it is of simple sturdy construction, free of small parts, which are subject to wear and are easily lost, so commonly associated with the handle-erecting devices of compasses.

Another advantage is that it provides strong friction means for holding the legs at any desired angular setting, said friction means being easily adjusted and little subject to wear.

Another advantage is that the pins through the erecting piece can be made to extend from both sides into the branches of the legs, and, as a result, the forces applied to the pins and to the erecting piece, by opening and closing the legs,

are symmetrical about two vertical planes of symmetry through the hinge of the compass, namely, about a vertical plane midway between the bifurcations of the compass legs and about another vertical plane perpendicular to the first plane and passing through the axis of the hinge pin. Because of this symmetry of forces about the hinge pin, there is no twisting action tending to develop lost motion or looseness in the hinge.

From the foregoing description taken in connection with the accompanying drawings, the uses, advantages, and operation of the compass of my invention will be readily understood by those skilled in the art to which the invention appertains. While I have described the form of my invention which I now consider to be the best embodiment thereof, I desire to have it understood that the compass shown is merely illustrative and that the invention is not to be limited to the details disclosed herein, but is to be accorded the full scope of the appended claims.

I claim:

1. A friction compass comprising a pair of non-overlapping legs each of which is bifurcated, a hinge pin, said legs having pivotal bearing surfaces abutting opposite sides of said hinge pin in facing relation, means for holding said legs in pivotal contact with said hinge pin, a spacing member slidably mounted between the branches of said legs, said slidable spacing member being provided with a slot having parallel sides closely fitting against said hinge pin and being so operatively connected to said legs that the axis of symmetry of said slidable spacing member substantially bisects the angle formed by said legs in any position, and means for holding the branches of said legs against said slidable spacing member in order to provide friction between said legs and said slidable spacing member.

2. A friction compass comprising a pair of nonoverlapping legs each of which is bifurcated, a hinge pin, means for holding said legs in pivotal contact with said hinge pin, a spacing member slidably mounted between the bracnhes of said legs, said slidable spacing member being provided with a handle and with two pins, each of which pins extends into holes in both branches of one of said compass legs, and means for frictionally holding the branches of said legs against said slidable spacing member.

FRANCIS E. VAUGHAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 432,578 Stevens July 22, 1890 434,742 Toquet Aug. 19, 1890 591,348 Fay Oct. 5, 1897 723,041 Schwarzer Mar. 17, 1903 730,388 Qberbeck June 9, 1903 902,257 Schoenner Oct. 2'7, 1908 953,026 Evans Mar. 29, 19.10

2,074,102 Christy Mar. 16, 1937 FOREIGN PATENTS Number Country Date 266,888 Germany Nov. 4, 1913 

